Patent application title: VIBRATING SYSTEM OF PANEL FORM ELECTRODYNAMIC LOUDSPEAKER

Abstract:

The present invention discloses a vibrating system of flat-plate
electrodynamic loudspeaker, which comprises a flat-plate vibrating plate
and a voice coil mounted under the vibrating plate. The vibrating system
is characterized in that the thickness of the vibrating plate within the
voice coil is not more than 1/2 of that of the vibrating plate outside
the voice coil. Alternatively, the vibrating plate within the voice coil
can be replaced by a vibrating diaphragm. The thin plate within the voice
coil according to the present invention can provide compensation for high
frequency response, widen frequency band, and reduce the overall height
of voice coil and vibrating plate. According to the present invention, a
thin flat-plate loudspeaker that almost cover the full audio frequency
bands can be designed, thereby producing a thin flat-plate full frequency
speaker system to meet the demand of market.

Claims:

1. A vibrating system of a flat-panel electrodynamic loudspeaker,
comprising: a flat-panel vibrating plate and a voice coil mounted under
the vibrating plate, wherein a thickness of the vibrating plate where the
voice coil is mounted is not more than 1/2 of the thickness of the
vibrating plate outside the voice coil.

2. The vibrating system of flat-panel electrodynamic loudspeaker according
to claim 1, wherein the thickness of the vibrating plate where the voice
coil is mounted is not more than 3 mm.

3. The vibrating system of flat-panel electrodynamic loudspeaker according
to claim 1, wherein the vibrating plate wherein the voice coil is mounted
is a vibrating diaphragm.

4. The vibrating system of flat-panel electrodynamic loudspeaker according
to claim 3, wherein the said vibrating diaphragm is a planar diaphragm or
a curved surface diaphragm.

5. The vibrating system of flat-panel electrodynamic loudspeaker according
to claim 1, wherein a circular recess or a circular through hole is
formed in the vibrating plate at the position where the voice coil is
mounted, wherein the voice coil is attached firmly to a side wall of the
recess or the through hole.

6. The vibrating system of flat-panel electrodynamic loudspeaker according
to claim 1, wherein a circular through hole is formed in the vibrating
plate at a place where the voice coil is mounted, wherein the voice coil
is attached to a side wall of the through hole, and the vibrating plate
and a bobbin of the voice coil form an integrated member.

7. The vibrating system of flat-panel electrodynamic loudspeaker according
to claim 6, wherein the vibrating plate where the voice coil is mounted
is a vibrating diaphragm positioned at a top of the bobbin of the voice
coil.

8. The vibrating system of flat-panel electrodynamic loudspeaker according
to claim 7, wherein the vibrating diaphragm positioned at the top of the
bobbin of the voice coil inosculates or is flush with the top of the
vibrating plate outside the voice coil.

9. The vibrating system of flat-panel electrodynamic loudspeaker according
to claim 7, wherein the bobbin of the voice coil is an aluminum roofed
cylinder, with a roof forming the vibrating diaphragm directly.

10. The vibrating system of flat-panel electrodynamic loudspeaker
according to claim 1, wherein the vibrating plate is circular and not
less than 8 cm in diameter, and a plurality of voice coils of small size,
each of which voice coil has a radius not more than a nodal radius of the
first-order resonance mode of the whole vibrating plate, are distributed
on the nodal circle of the first-order resonance mode.

11. The vibrating system of flat-panel electrodynamic loudspeaker
according to claim 6, wherein the flat-panel vibrating plate has one or
more through holes, at least in one of which the voice coil is mounted,
wherein the vibrating plate at the top of the voice coil and the bobbin
of the voice coil are integrated.

12. The vibrating system of flat-panel electrodynamic loudspeaker
according to claim 2, wherein a circular recess or a circular through
hole is formed in the vibrating plate at position where the voice coil is
mounted, wherein the voice coil is attached firmly to the side wall of
the recess or the through hole.

13. The vibrating system of flat-panel electrodynamic loudspeaker
according to claim 3, wherein a circular recess or a circular through
hole is formed in the vibrating plate at position where the voice coil is
mounted, wherein the voice coil is attached firmly to the side wall of
the recess or the through hole.

14. The vibrating system of flat-panel electrodynamic loudspeaker
according to claim 4, wherein a circular recess or a circular through
hole is formed in the vibrating plate at position where the voice coil is
mounted, wherein the voice coil is attached firmly to the side wall of
the recess or the through hole.

15. The vibrating system of flat-panel electrodynamic loudspeaker
according to claim 2, wherein a circular through hole is formed in the
vibrating plate at a place where the voice coil is mounted, wherein the
voice coil is attached to a side wall of the through hole, and the
vibrating plate and a bobbin of the voice coil form an integrated member.

16. The vibrating system of flat-panel electrodynamic loudspeaker
according to claim 3, wherein a circular through hole is formed in the
vibrating plate at a place where the voice coil is mounted, wherein the
voice coil is attached to a side wall of the through hole, and the
vibrating plate and a bobbin of the voice coil form an integrated member.

17. The vibrating system of flat-panel electrodynamic loudspeaker
according to claim 4, wherein a circular through hole is formed in the
vibrating plate at a place where the voice coil is mounted, wherein the
voice coil is attached to a side wall of the through hole, and the
vibrating plate and a bobbin of the voice coil form an integrated member.

18. The vibrating system of flat-panel eletrodynamic loudspeaker according
to claim 2, wherein the vibrating plate is circular and not less than 8
cm in diameter, and a plurality of voice coils of small size, each of
which voice coil has a radius not more than the nodal radius of the
first-order resonance mode of the whole vibrating plate, are distributed
on a nodal circle of the first-order resonance mode.

19. The vibrating system of flat-panel eletrodynamic loudspeaker according
to claim 3, wherein the vibrating plate is circular and not less than 8
cm in diameter, and a plurality of voice coils of small size, each of
which voice coil has a radius not more than the nodal radius of the
first-order resonance mode of the whole vibrating plate, are distributed
on a nodal circle of the first-order resonance mode.

20. The vibrating system of flat-panel eletrodynamic loudspeaker according
to claim 4, wherein the vibrating plate is circular and not less than 8
cm in diameter, and a plurality of voice coils of small size, each of
which voice coil has a radius not more than the nodal radius of the
first-order resonance mode of the whole vibrating plate, are distributed
on a nodal circle of the first-order resonance mode.

Description:

FIELD OF THE INVENTION

[0001]The present invention relates to an improved vibrating system of
flat-panel electrodynamic loudspeaker.

BACKGROUND OF THE INVENTION

[0002]Presently, as flat-panel TV is thriving, the demand of flat-panel or
thin-type speaker system in match with the flat-panel TV is increasing
significantly. There are three categories of such speaker system. One
category is extra-thin speaker system designed according to
bending-panel-vibrating principle disclosed in NXT (U.K.) patent, the
second one being thin-type speaker system manufactured by using the
common cone loudspeaker, and the third one being flat-panel speaker
system manufactured by using conventional flat-panel loudspeaker.

[0003]Among them, the flat-panel loudspeaker has a long history and there
has been some new development thereof, such as BES patent, multi-drive
technology, coaxial flat-panel loudspeaker technology etc. However, these
newly developed technologies have their own problem that the upper limit
of the high frequency band can not extend to cover the full audio
frequency range, and the flat-panel loudspeaker has a comparably large
thickness, high cost of production, difficulty in its manufacture
process.

[0004]As for the NXT's patent technology, there remain two problems. The
first problem is that it cannot cover full frequency range, and thus
subwoofer speaker system should be needed additionally for frequency
below 200 Hz. The second problem is that in the high frequency range, the
sound pressure response is not flat while a flat power response can be
achieved. It means that the loudspeaker has a non-flat transient
frequency response and a flat long-time average response, which shall
lead to bad listening. The thin type speaker system designed with
conventional loudspeakers has firstly large thickness, which may be over
6 cm in general, thus hard to match with the flat-panel TV, and secondly
has a heavy weight, hard to be hang on the wall.

[0005]Clearly there exists a demand for a thin type full-range flat-panel
loudspeaker, which could cover all the audio range.

SUMMARY OF THE INVENTION

[0006]The object of the present invention is to meet the demand of market
by providing a new structure of vibrating system of flat-panel
eletrodynamic loudspeaker, thereby achieving a thin flat-panel
loudspeaker capable of covering the whole audio frequency range and
manufacturing a thin flat-panel full-frequency-range speaker system.

[0007]The vibrating system of flat-panel electrodynamic loudspeaker
according to the present invention comprises a flat-panel vibrating plate
and a voice coil mounted under the vibrating plate. The vibrating system
is characterized in that the vibrating plate within the voice coil has a
thickness not more than 1/2 of thickness of the vibrating plate outside
the voice coil.

[0008]In order to achieve a good compensation effect in high frequency
range, a preferred design is to let the vibrating plate within the voice
coil have a thickness not more than 3 mm.

[0009]Further preferably, the vibrating plate within the voice coil can be
replaced by vibrating diaphragm, and this vibrating diaphragm may be a
planar vibrating diaphragm, or a curved-surface vibrating diaphragm, such
as a dome type diaphragm of a conventional tweeter loudspeaker.

[0010]In the vibrating system of loudspeaker according to the present
invention, there is a thick vibrating plate outside the voice coil and a
thin vibrating plate within the voice coil, wherein the thickness of the
plate within the voice coil is significantly less than that of the plate
outside the voice coil. According to the concept of the present
invention, the flat-panel vibrating plate and the voice coil mounted
under the vibrating plate can be structured as below: A circular recess
or circular through hole is formed in the vibrating plate at place where
the voice coil is to be mounted. In case of the circular recess, a thin
plate (with a thickness not more than 1/2 of that of the whole vibrating
plate) formed at the bottom of the recess functions as the vibrating
plate within the voice coil. In case of the circular through hole, said
vibrating diaphragm will be used to cover the circular through hole. The
voice coil is attached firmly to the side wall of the recess or the
through hole. Thus, the contact area between the voice coil and the
vibrating plate will be increased significantly. According to prior art,
only a ring on top of the voice coil contacts with the vibrating plate,
which may be referred as `line contact`. However, in the present
invention, it is a section of cylindrical surface with certain height
that contacts with the vibrating plate, and thus may be referred as `area
contact`. The present invention has a much larger contact area than the
prior art, thus the contact strength can be significantly enhanced,
thereby decreasing the overall height of the voice coil and the vibrating
plate.

[0011]For a square vibrating plate adopting multi-drive scheme and
small-sized circular vibrating plate, the above technique may be applied
directly due to their voice coils having small diameter.

[0012]For a vibrating system of flat-panel electrodynamic loudspeaker with
circular vibrating plate of larger size, the conventional design uses a
voice coil having the nodal diameter of the first-order resonance mode of
the vibrating plate (about 0.68-0.7 times the diameter of the vibrating
plate) as the drive, which may be referred as "single-drive". If a thin
vibrating plate is adopted in a voice coil with such a big size, a
problem of insufficient strength may arise. To overcome this problem, a
solution with multi-drive by a plurality of voice coils may be adopted.
In this solution, when said vibrating plate is a round plate with a
diameter not less than 8 cm, a plurality of voice coils of small size,
radius of each of which is not more than the nodal radius of the
first-order resonance mode of the vibrating plate, will be distributed on
the nodal circle of the first-order resonance mode of the whole vibrating
plate. In this way, thin vibrating plates provided within these small
size voice coils can offer compensation for high frequency, and avoid the
problem regarding strength in case of the wide-area thin plate.

[0013]A further improvement is provided based on the above technical
solution. A circular through hole is formed in the vibrating plate at
place where a voice coil is to be mounted. To side wall of the through
hole is attached firmly the voice coil, at the top of which a vibrating
diaphragm integrating with the bobbin of the voice coil is provided. The
vibrating diaphragm may be any forms of conventional dome diaphragm, such
as flat-topped, convex or concave-topped diaphragm. It is preferred that
the vibrating diaphragm at the top of the voice coil should inosculate or
be flush with the top of the vibrating plate when assembling.

[0014]The vibrating diaphragm at the top of the voice coil may integrate
with the bobbin of the voice coil. The bobbin of the voice coil may be a
roofed cylinder, such as an aluminum roofed cylinder. The top roof
surface of the cylinder functions as a diaphragm, and lower section of
the cylinder is wound with coils, thereby forming an integral diaphragm
and voice coil.

[0015]The above improvement may fit also for the case of multi-driving
with a plurality of voice coils. In this case, the panel vibrating plate
has one or more through holes. On at least one of the through holes is
mounted a voice coil, at the top of which vibrating diaphragm and the
bobbin are integrated.

[0016]In the above solution, the integral vibrating diaphragm and the
voice coil are combined with the vibrating plate having through hole(s),
so that the top of the aluminum cylinder inosculates or is flush with the
top of the vibrating plate. In this way, not only the assembly is
simplified, but also the bonding between the vibrating diaphragm and the
voice coil is made to be firm, thus further improving high frequency
response and ensuring consistency of performance of the loudspeakers. In
the case of an aluminum roofed cylinder being used, the aluminum integral
diaphragm at the top of the cylinder can greatly improve heat elimination
effect of the voice coil and thus improve the ability of power handing of
the loudspeaker.

[0017]The present invention may be applied to driving with a plurality of
voice coils, to reduce assembling difficulty and improve homogeneity of
products.

[0018]The important technical characteristics and the important technical
effect therefrom according to the present invention is that the part of
thin vibrating plate within the voice coil contributes to a major portion
of high frequency sound produced by the whole vibrating plate. Thus, the
sound is produced by the whole vibrating plate in low and middle
frequency range, but when moving to high frequency range, the sound is
gradually produced mainly by the thin section of the vibrating plate
within the voice coil driven directly by the voice coils. The present
invention introduces a compensation part for high frequency into the
flat-panel vibrating plate, thereby achieving an effect similar to the
"coaxial" loudspeaker. Furthermore, the present invention solves the
problem as to how to get reasonable amplitude in a space with limited
thickness, because the reduced thickness of vibrating plate within the
voice coil provides room for the up-down movement of the vibrating
system.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is a schematic diagram of a vibrating system of single-drive
flat-panel loudspeaker according to the present invention;

[0020]FIGS. 2 and 3 are schematic diagrams of a vibrating system of
single-drive flat-panel loudspeaker, in which the vibrating plate within
voice coil is a vibrating diaphragm, according to the present invention,
wherein FIG. 2 is its front view and FIG. 3 is its top view;

[0021]FIGS. 4 and 5 are schematic diagrams of a first vibrating system of
multi-drive flat-panel loudspeaker according to the present invention,
wherein FIG. 4 is a front view and FIG. 5 is a top view;

[0022]FIGS. 6 and 7 are schematic diagrams of a second vibrating system of
multi-drive flat-panel loudspeaker according to the present invention,
wherein FIG. 6 is a front view and FIG. 7 is a top view;

[0023]FIGS. 8 and 9 are schematic diagrams of a third vibrating system of
multi-drive flat-panel loudspeaker according to the present invention,
wherein FIG. 8 is a front view and FIG. 9 is a top view;

[0024]FIGS. 10 and 11 are two schematic diagrams of a fourth vibrating
system of multi-drive flat-panel loudspeaker according to the present
invention, wherein FIG. 10 is a front view and FIG. 11 is a top view; and

[0025]FIG. 12 is a schematic diagram of an exploded view of an improved
vibrating system of flat-panel loudspeaker according to the present
invention.

DETAILED DESCRIPTION OF THE INVENTION

Embodiment 1

[0026]In this embodiment, there is provided a vibrating system of a
single-drive flat-panel loudspeaker. As shown in FIG. 1, a vibrating
plate 1 of the vibrating system is made of lightweight foam plate with
φ5 cm and 0.5 cm thick, on which a voice coil 3 with φ2.8 cm is
mounted. The vibrating plate 2 in the voice coil is reduced in thickness
to 0.1 cm to compensate for high frequency response. A circular recess is
formed in the vibrating plate at place where the voice coil is to be
mounted, and the voice coil 3 is attached to the side wall of the recess.

Embodiment 2

[0027]In this embodiment, there is provided another vibrating system of
single-drive flat-panel loudspeaker. As shown in FIGS. 2 and 3, a
vibrating plate 1 of the vibrating system is made of lightweight foam
plate with φ5 cm and 0.5 cm thick, on which a voice coil 3 with
φ2.8 cm is mounted. The vibrating plate within the voice coil is
replaced by a vibrating diaphragm 4. A circular through hole is provided
in the vibrating plate at place where the voice coil is to be mounted and
the hole reaches the top of the vibrating plate. There is a planar
vibrating diaphragm 4 covering the top of the circular through hole. The
voice coil 3 is attached to the inner side wall of the through hole. The
bobbin of the voice coil extends to the top of the vibrating plate 1 and
is connected to the vibrating diaphragm 4.

Embodiment 3

[0028]In this embodiment, there is provided a vibrating system of
multi-drive flat-panel loudspeaker with a square flat-panel vibrating
plate. As shown in FIGS. 4 and 5, a vibrating plate 1 is made of
lightweight foam plate with 10×10×1 cm (L×W×H).
At the nodal line of the first-order resonance mode of the vibrating
plate, i.e. at 4 off-center positions, four voice coils 3 with 2.5 cm are
mounted. Circular recesses matching in size with the voice coils are
formed in advance at respective positions where each of the voice coils
will be mounted, and thin vibrating plates 2 with thickness of 2 mm are
formed at the top of the recesses. The voice coils 3 can be inserted
exactly into the recesses and attached to the vibrating plate well by
adhesion using glue. Thus, the thin plate within the voice coil can
provide compensation for high frequency response, thereby extending the
frequency band.

Embodiment 4

[0029]In this embodiment, there is provided a vibrating system of
multi-drive flat-panel loudspeaker with a circular flat-panel vibrating
plate. As shown in FIGS. 6 and 7, the vibrating plate 1 is made of
lightweight foam plate with φ11 cm and with thickness of 1 cm, and 4
voice coils are distributed uniformly on the nodal circle of the
first-order resonance mode of the vibrating plate (having a diameter
about φ7-8 cm, and could be determined by experiment). The vibrating
plate 2 within the voice coil is 0.2 cm thick, thereby compensating for
high frequency response.

Embodiment 5

[0030]In this embodiment, there is provided a vibrating system of
multi-drive flat-panel loudspeaker with a circular flat-panel vibrating
plate. As shown in FIGS. 8 and 9, the vibrating plate 1 is made of
lightweight foam plate with φ11 cm and with thickness of 1 cm. Four
circular holes, each with φ2.5 cm, are provided uniformly on the
nodal circle of the first-order resonance mode (about φ7-8 cm). Four
voice coils 3, each with φ2.5 cm, are respectively mounted in the
through holes. The bobbins of the voice coils extend to the top of the
vibrating plate. The upper surface of the vibrating plate is covered by a
vibrating diaphragm made of fabric so that a close connection is formed
between the fabric and the vibrating plate 1 and the voice coils. Thus, a
vibrating diaphragm 5 made of fabric is formed on the voice coils 3. In
this way, the sound in the high frequency range is produced mainly by the
4 vibrating diaphragms with φ2.5 cm driven directly by the voice
coils, thereby compensating for high frequency response effectively.

Embodiment 6

[0031]In the embodiment, there is provided a vibrating system of
multi-drive flat-panel loudspeaker with circular flat-panel vibrating
plate. As shown in FIGS. 10 and 11, the vibrating plate 1 is made of
lightweight foam plate with φ11 cm and with thickness of 1 cm. Four
φ2.5 cm circular holes are provided uniformly on the nodal circle of
the first-order resonance mode of the vibrating plate (a circle with
about φ7-8 cm), and then 4 voice coils 3 with φ2.5 cm are mounted
in these holes, with their bobbins extending to the top of the vibrating
plate. Further, a concave dome tweeter diaphragm 6 is provided on each of
the voice coils 3, so as to compensate for high frequency response.

Embodiment 7

[0032]In this embodiment, there is provided an improved vibrating system
of single-drive flat-panel vibrating plate. As shown in FIG. 12, the
vibrating plate 1 of the system is made of a lightweight foam plate with
φ5 cm and with thickness of 0.5 cm. An improved voice coil 3 with
φ2.8 cm is attached firmly to the vibrating plate. The voice coil 3
has an aluminum roofed cylinder, with the roof functioning as a vibrating
diaphragm (i.e., an aluminum diaphragm). At lower portion of the cylinder
is wound with coil, thereby forming an integrated vibrating diaphragm and
voice coil. The voice coil 3 is attached firmly to side wall of the
circular through hole in the center of the vibrating plate 1. The top of
the aluminum cylinder inosculates the top of the vibrating plate.